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A207244 Number of 4Xn 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 0 1 0 vertically 1
9, 81, 287, 987, 2884, 7165, 17929, 40646, 90602, 196548, 412733, 859077, 1751887, 3532169, 7052859, 13932019, 27335037, 53236611, 103050502, 198448577, 380245761, 725544748, 1379004108, 2611731954, 4930796893, 9281596371 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 4 of A207242

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 5*a(n-1) -4*a(n-2) -12*a(n-3) +3*a(n-4) +47*a(n-5) -17*a(n-6) -66*a(n-7) -9*a(n-8) +90*a(n-9) +2*a(n-10) -33*a(n-11) +a(n-12) -5*a(n-13) -44*a(n-14) +19*a(n-15) +52*a(n-16) -16*a(n-17) -7*a(n-18) -3*a(n-19) +a(n-20) -18*a(n-21) +17*a(n-22) -2*a(n-23) +2*a(n-24) -3*a(n-25) +3*a(n-26) -3*a(n-27) +a(n-28)

EXAMPLE

Some solutions for n=4

..0..0..1..0....1..0..0..1....0..1..0..1....1..1..1..1....0..1..0..0

..0..1..0..0....0..1..0..1....0..0..1..0....1..1..1..1....0..0..1..0

..0..1..0..0....1..1..0..1....0..0..1..0....1..1..1..1....0..0..1..0

..0..1..0..0....1..0..0..1....0..0..1..0....0..1..0..1....0..0..1..0

CROSSREFS

Sequence in context: A207238 A207496 A208165 * A207064 A207119 A207399

Adjacent sequences:  A207241 A207242 A207243 * A207245 A207246 A207247

KEYWORD

nonn

AUTHOR

R. H. Hardin Feb 16 2012

STATUS

approved

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Last modified September 25 07:19 EDT 2022. Contains 356959 sequences. (Running on oeis4.)